Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Dalian Minzu University, 18 Liaohe Road West, Dalian Economic and Technological Development Zone, Dalian, 116600, China; College of Environment and Resources, Dalian Minzu University, Dalian, 116600, China; Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Yokohama, 223-8522, Japan.
Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Yokohama, 223-8522, Japan.
Chemosphere. 2020 Jul;251:126364. doi: 10.1016/j.chemosphere.2020.126364. Epub 2020 Mar 2.
This study is among the first to systematically study the electrochemical reduction of nitrate on boron-doped diamond (BDD) films with different surface terminations and boron-doping levels. The highest nitrate reduction efficiency was 48% and the highest selectivity in the production of nitrogen gas was 44.5%, which were achieved using a BDD electrode with a hydrogen-terminated surface and a B/C ratio of 1.0%. C-H bonds served as the anchor points for attracting NO anions close to the electrode surface, and thus accelerating the formation of NO. Compared to oxygen termination, hydrogen-terminated BDD exhibited higher electrochemical reactivity for reducing nitrate, resulting from the formation of shallow acceptor states and small interfacial band bending. The hydrophobicity of the hydrogen-terminated BDD inhibited water electrolysis and the subsequent adsorption of atomic hydrogen, leading to increased selectivity in the production of nitrogen gas. A BDD electrode with a boron-doping level of 1.0% increased the density of acceptor states, thereby enhancing the conductivity and promoting the formation of C-H bonds after the cathodic reduction pretreatment leading to the direct reduction of nitrate.
这项研究是首次系统地研究不同表面终止和硼掺杂水平的掺硼金刚石（BDD）薄膜上硝酸盐的电化学还原。使用具有氢化表面和 B/C 比为 1.0 的 BDD 电极，实现了最高 48%的硝酸盐还原效率和最高 44.5%的氮气生成选择性。C-H 键作为吸引靠近电极表面的 NO 阴离子的锚定点，从而加速了 NO 的形成。与氧终止相比，氢化 BDD 对硝酸盐还原表现出更高的电化学活性，这是由于形成浅受主态和小的界面能带弯曲所致。氢化 BDD 的疏水性抑制了水电解和随后的原子氢吸附，从而提高了氮气生成的选择性。硼掺杂水平为 1.0%的 BDD 电极增加了受主态密度，从而增强了导电性，并促进了在阴极还原预处理后形成 C-H 键，从而直接还原硝酸盐。
